The invention is based on a wiper blade with a wiper strip that is held by a support bracket system and which is encompassed by a protective profile.
Known wipers have a wiper arm, which is comprised of a fastening part that is attached to a drive axle, a hinge part connected to it via a toggle joint, and a wiper rod rigidly connected to the hinge part. The wiper also has a wiper blade with a support bracket system and a wiper strip supported by this support bracket system. The wiper blade is attached to the wiper arm by virtue of the fact that a hook-shaped end of the wiper rod engages between two side walls of the support bracket system and encloses a hinge pin. The resulting hinge guides the wiper blade with the wiper strip over a motor vehicle window, wherein the hinge part and the support bracket system make it possible for the wiper strip to adapt to a curvature of the motor vehicle window. A required pressure of the wiper strip against the motor vehicle window is achieved with at least one tension spring which braces the fastening part and the hinge part together with the wiper rod by means of the toggle joint.
The wiper strip is comprised of an elastomer, e.g. a natural or synthetic rubber, or of ethylene propylene. It has a top strip which is connected via a tilting rib to a wiper lip that rests against the window to be wiped. By means of the tilting rib, the wiper lip can turn over at a reversal point of the wiping direction, into the opposite direction so that it always assumes a favorable angle in relation to the windshield. When the wiper is actuated, the wiper strip sweeps with the wiper lip across the motor vehicle window, wherein it gets worn down by friction between the wiper lip and the windshield. In addition, environmental influences act on the wiper strip, e.g. temperature fluctuations, UV radiation, salt water, exhaust, etc., which can lead to a premature aging of the material and to an increased wear.
A known strategy for assuring that the wiper strip is in perfect condition when a new motor vehicle is delivered is to cover the wiper strip with a protective profile before the vehicle is conserved. The protective profile is only removed when the new motor vehicle is transferred to a buyer after a final conservation. However, if the windshield becomes soiled or the visibility is hindered by rain when the motor vehicle is in temporary storage or during conservation, the windshield cannot be cleaned with the wiper system for purposes of maneuvering the vehicle. The protective profile is rigid, hard, and rests only partially against the windshield.
DE 30 05 965 A1 has proposed fastening the longitudinal edge of a flexible band to the side of the protective profile oriented toward the windshield. The protective profile is comprised of hard PVC and the band is comprised of soft PVC. If the wiper is actuated, the band is turned over more or less over the length of the wiper blade and is therefore in a position to adapt to the curvature of the windshield within certain limits. The band functions as a wiper lip, as a result of which the wiper system can be used to clean the windshield during maneuvers without using the actual wiper strip of the wiper blade. During conservation processes of the motor vehicle, however, the flexible band is frequently exposed to high temperatures. The band becomes embrittled, the elasticity is reduced, the turning process is impaired, and the wiping quality deteriorates.
The support bracket system of the wiper blade permits the wiper strip to adapt to curvatures of the windshield. A protective profile, which is comprised of an elastic material and can adapt largely, preferably completely, to curvatures of the windshield by means of elastic deformation, preserves the function of the support bracket system for the protective profile, which is otherwise lost when the protective profile is rigid. The wiper element, which is fastened with a bottom side to the protective profile, rests against the windshield uniformly over the length of the wiper blade during the wiping motion and a favorable wiping quality can be achieved. A turning over of the wiper element is not required for adaptation to the windshield. Instead of a tall, thin lip, which rapidly embrittles under the effects of heat, a wiper element can be used which has an approximately square, trapezoidal, or triangular cross-sectional area. Because of material accumulation, the wiper element is resistant to environmental influences, is particularly resistant to heat, and essentially retains its properties. Fundamentally, however, the turning over of a tall wiper element and/or the plastic and elastic deformation of the wiper can be used in conjunction with the elastically deformable protective profile to better adapt the wiper element to curvatures of the windshield. Preferably, the wiper element is comprised of a thermoplastic elastomer, i.e. of a combination of a thermoplastic and an elastomer. With a combination of this kind, particularly heat resistant materials can be produced, which can adapt favorably to curvatures of windshields by means of plastic and elastic deformation. Despite heat treatment with high temperatures or a conservation of the motor vehicle, a favorable wiping quality can be achieved with the wiper element.
The section modulus of the protective profile and the capacity to adapt to various curvatures of the windshield during the wiping motion depends on the material and the cross sectional geometry of the protective profile. The protective profile is preferably comprised of elastic plastic, in particular such as polypropylene, which remains elastically deformable at high temperatures of up to approx. 80xc2x0 C. Plastic is reasonably priced, lightweight, and easy to process. Fundamentally, however, the protective profile can also be partially or completely made of metal.
The protective profile is comprised of a tubular or sleeve-shaped, elongated profile which encompasses the wiper strip with two side walls and is fastened with claw-like projections to the wiper strip or the wiper blade. One embodiment of the invention proposes a cross sectional geometry in which the profile tapers from the wiper strip toward the windshield and each side wall has one or several turning points, preferably two of them. The turning points constitute shoulder points for an elastic deformation, which encourage this elastic deformation. In addition, the elastic deformability is encouraged by means of a profile that is rounded toward the windshield, preferably in the shape of a pear, and by means of a wall thickness of less than 0.8 mm.
A known strategy for fastening the protective profile to the wiper blade in captive fashion and protecting the wiper strip laterally from environmental influences is to weld the protective profile shut laterally. To this end, the protective profile is heated on the lateral ends and is pressed against a plate. A material plate is produced which does close the protective profile but also stiffens it. In one embodiment, the proposal is made to close the protective profile in the longitudinal direction with a cover on at least one end, which can be used to advantageously open and close the protective profile a number of times for installation and removal. The cover can be slid onto the protective profile and can be fastened to the protective profile by means of a detachable frictionally and/or positively engaging connection. In addition, the cover can be connected to the protective profile in captive fashion and can be fixed in a closed position and/or an open position by means of detent means, for example in a cover, which is connected to the protective profile in captive fashion via a hinge, by means of a rotating motion, or in a cover which is connected to the protective profile via a strip, by means of a straight linear motion, etc.
The installation and removal of the protective profile is facilitated with the cover according to the invention and in particular, by means of a cover, a lateral stiffening of the protective profile can be largely prevented and the elastic deformability can be maintained, for example by virtue of the fact that the cover is fastened with play, can be displaced within limits, and/or rests only partially against the protective profile. Furthermore, the elastic deformability can be maintained by virtue of the fact that the entire end is not reshaped into a material plate, but rather, the protective profile is closed with a projection which is directed inward, lateral to the longitudinal direction and is formed onto a side wall of the protective profile. The projection is produced, for example, by means of a heat source or preferably by means of an ultrasonic source.